Combustion heater with fuel retaining trough and igniter pocket



May 31, 1 H. J. DE N. M COLLUM COMBUSTION HEATER WITH FUEL RETAINING THOUGH AND IGNITER POCKET 4 Sheets-Sheet 1 Filed Oct. 3, 1945 y 1949- J. DE N. M COLLUM 2,471,833

COMBUSTION HEATER WITH FUEL RETAINING TROUGH AND IGNITER POCKET Filed OCt. 3, 1945 4 Sheets-Sheet 2 May 31, 1949- H. J. DE N. McCOLLUM COMBUSTION HEATER WITH FUEL RETAINING THOUGH AND IGNITER POCKET 4 Sheets-Sheet 3 Filed 001;. 3, 1945 @Izwea; [Wt/La,

, ,2 allow-x 1 S May 31, 1 4 H. J. DE N. M COLLUM COMBUSTION HEATER WITH FUEL RETAINING TROUGH AND IGNITER POCKET 4 Sheets-Sheet 4 Filed Oct. 3, 1945 0 1 i a z n M 0 Nt a w 0 w 2 2 M 0a affair 4 3 Fig. 2 is an end elevation indicated on line 5-5 Patented May 31, 1949 r 2,471,833 COMBUSTION HEATER WITH FUEL RETAIN- ING TROUGH tion, Chicago, 111.,

AND IGNITER POCKET Henry J. De N.McCollum, cago, 11L, by Thelma M cago, Ill., assignor to S deceased, late of ChicCollum, executrix, Chitewart-Warner Corporaa corporation oi Virginia Application mm 3, 1945, Serial No. 619,980

4 Claims.

This invention relates to internal combustion heaters and is particularly concerned with the type in which the fuel arrives at the combustion chamber in liquid form and is there mixed with air for combustion.

One object of the invention is to provide means for insuring a proper intermixture of the air and liquid fuel without employing a spray nozzle for breaking up the fuel, or premixing means anterior to the burner.

Another object of the invention is to provide a combustion chamber into which the fuel is introduced in liquid form, the chamber itself being shaped to providea trough to retain liquid fuel until it is vaporized by the heat of the combustion chamber and by contact with the air introduced therein.

It is also an object of the invention to provide an internal combustion heater with a combustion chamber having a portion in which combustion of the fuel is initiated, together with a pocket adjoining said portion of the combustion chamber with means for delivering liquid fuel to the pocket and ignition means in the pocket capable of at least partially vaporizing such liquid fuel and igniting the vapor for admixture with air introduced into the bustion chamber.

A furtherobject of the invention is to provide an 'internal combustion heater having a combusadjoining portion of the comtion chamber with means for introducing combustion air into a portion of the chamber, and ignition means closely adjoining said portion of the combustion chamber but protected from the air flow in a manner which prevents cooling of the ignition means.

Other objects and advantages of the invention will appear from the following description taken in connection with the drawings, in which:

Fig. 1 is a, vertical axial sectional view of an internal combustion heater which includes certain features embodying this invention;

of the heater shown in Fig. 1, as indicated in line 2-2 on Fig. 1;

Fig. 3 is a vertical sectional view of a heater embodying a modification of the invention, a portion of the heater being broken out to condense the view;

Fig. 4 is a transverse detail section taken as indicated on line 4-4 of Fig. 3;

Fig. 5 is a transverse sectional view taken as of Fig. 3, and on a larger scale;

Fig. 6 is a fragmentary vertical sectional view of a heater embodying another modification of the invention;

Fig. 7 is a fragmentary vertical sectional view showin another modified form of the invention;

Fig. 8 is a fragmentary sectional view similar to Fig. 7, but showing a further modification;

Fig. 9 is a, detail section taken as indicated on line 99 of Fig. 8.

In heaters of the internal combustion type, one of the major difficulties in employing liquid fuel involves obtaining adequate intermixture of the fuel and air, and to meet this problem spray nozzles are sometimes used to atomize the fuel, or premixing burners are employed, in which the fuel and air are more or less mechanically intermingled before introduction into the combustion chamber. The present invention undertakes to dispense with the use of spray nozzles or premixers and to accomplish a satisfactory intermingling of fuel and air in the combustion chamber itself with the aid of relatively simple structural features.

In each form of the invention herein illustrated, the fuel is delivered in liquid form and at least a portion of the fuel is received in liquid form in a pocket closely adjoining the combustion chamber and communicating therewith. The igniting means is arranged in the pocket thereto so that a portion of the fuel will be promptly vaporized by the heat of the igniter and then ignited in the pocket, whichthus becomes a portion of the combustion chamber. In addition, the portion of the combustion chamber adjoining the pocket is so shaped as to serve as a trough to retain fuel which may not be immediately vaporized and to prevent it from escaping into the general combustion space until it has been properly vaporized and mixed with combustion air.

As shown in Fig. 1, the heater is of the type arranged for heating water which may serve as the heat transmitting medium or vehicle in a system havin radiators through which the water is circulated. The heater includes a main combustion space I 0 surrounded by a water jacket l2 and with a second water jacket l4 spaced from the jacket l2 by an intermediate anular space [6 which communicates at one end with the combustion space In, and at the other end with an exhaust passage I 8. The water inlet pipe is shown a at 20 connecting with both water jackets l2 and or adjacent 28 which terminates in a right angle bend at 38,

delivery opening 40 in a block or fitting 42 secured to one side of the pocket 36 and an igniter 44 of the hot wire type is supported in the pocket 36 extending downwardly near the bottom wall thereof. This type of heater is designed to be mounted with the axis of its cylindrical chamber I8 and surrounding jackets in a substantially horizontal position so that the floor or bottom wall of the pocket 36 is normally horizontal, while the lower portion of the shell 32 is inclined upwardly from the end wall 34 toward the main combustion space I8.

Theliquid fuel introduced at 48 drips or flows on to the floor or bottom wall of the pocket 36,

\ and a portion of this fuel is readily vaporized by the radiant heat of the igniter 44. The air entering the shell 32 at 38 in tangential relation to the circular outline of the shell 32, sweeps around it with a whirling motion, entraining the vapor from the pocket 36 and forming a combustible mixture therewith. This mixture is initially ignited by contact with the igniter 44, and thereafter the additional vapor entering the shell 32 from the pocket 36 is ignited by contact with the flaming gas already burning therein. The tapered form of the shell 32 tends to confine the whirling mixture initially until combustion is well established because the centrifugal action operates to drive the liquid portion of the mixture toward the larger end of the shell 32 which is adjacent its end wall 34. The liquid particles are thus retained in the shell 32 and whirled about with the air until they are vaporized and more completely intermingled with the air, thus insuring more nearly perfect combustion.

Whenever the liquid fuel enters the pocket 36 more rapidly than it can be vaporized by the heat of the igniter 44 or the heat radiated from the combustion chamber itself, the excess of liquid fuel will run into the shell 32 and will accumulate in the lower portion thereof adjacent the back wall 34, which thus provides a trough at 33 in which the liquid fuel is retained but exposed to the whirling stream of air and to the heat of burning gases in the shell 32, so that this liquid fuel is rapidly changed to vapor and thoroughly mixed with air for combustion. As already indicated, combustion of the mixed fuel and air continues and proceeds longitudinally in the shell III, the products of combustion flowing toward the end wall I I and then reversing their direction and flowing through the space I6 to the exhaust passage I8.

Fig. 3 illustrates a slightly different form of heater, in which the purpose is to heat a stream of ventilating air flowing in heat exchange relation with the products of combustion. The cylindrical casing 58 encloses a motor 52 which drives a fan 54 for drawing ventilating air through the casing and through the longitudinal passages 56 which are provided between the turns of a. spirally formed passage 58 in which products of combustion flow from the combustion chamber 68. Air for combustion is drawn through the combustion space in a conduit 62 where it is preheated. From the conduit it is delivered to the central portion of a blower wheel 64 arranged to be driven by the same motor 52 which drives the fan 54, and this wheel delivers the air centrifugally into an air chamber 66 which jackets one end of the frusto conical shell 68 forming the burner or initial portion of the combustion chamber. The air enters the shell 68 through ports 16 therein and adjacent these ports the vanes 12 direct the flowing air tangentially against the inner surface of the shell 68 so that a whirling action of the air is thus produced within the burner shell. The larger end of the frusto conical shell 68 is closed by a flat wall 14, and a pocket 16 is secured against the outer face of the wall 14 but communicates with the interior of the shell 68 through ports 18 and 80 in the wall 14.

As shown in Fig. 5, a fuel inlet pipe 82 delivers fuel to the pocket 16 through an orifice 84, and

, the enclosing shell 86 of the hot wire igniter 88 is mounted in the pocket close enough to the orifice 84 so that the liquid fuel will become vaporized by passin near the igniter. However, if some of the liquid is not vaporized, it will collect in the bottom of the pocket and may drain through the lower portion of the port 88 into the larger end of the shell 68. At this point a trough 90 is formed to receive the liquid fuel and retain it until it can be vaporized and swept away by the whirling currents of air and combustible mixture in the shell '68. From'the shell 68 the products of combustion pass into the space 66 and thence throughthe spirally formed jacket 58 to the exhaust passage 92 leading therefrom. The details of this spiral heat exchanger form no part of the present invention and need not be further described in this connection.

When a frusto-conical shell is used for the initial portion or burner space of the combustion chamber as described, a substantial pressure drop is caused by the progressive constriction of the rotating air mass and by turbulence at the point where the products of combustion flow suddenly from the small diameter opening of the burner into the larger space. If less pressure drop is advisable, the arrangement shown in Fig. 6 is of advantage. The frusto-conical burner shell 94 is mounted within the outer casing 96 and is provided with a pocket 98 to which the fuel is fed through a pipe I00 and in which the igniter "I62 of the hot wire type is located. The combustion air is introduced at I64 and sets up a whirling action within the shell 94 in the same manner as in the forms of the invention already described. But instead "of feeding directly into the main combustion space I86 the conical shell 94 is connected by a short cylindrical portion I88 with a reversely frusto-conical or flaring section III! so that the three sections 94, I 88 and H0 approximate the form of a venturi and a large percentage of the pressure drop is recovered as the gases flow through the flaring section IIO into the space I06.

In the burner shell I12 shown in fragmentary fashion in Fig. 7, the bottom wall I14 of the pocket I16 adjoining the burner shell I12 is continuous with the wall of the shell I12, but a false bottom or pan I18 is provided in the pocket to receive the liquid fuel which drips from the feed orifice I88 to which the feed pipe I82 leads.

In this structure the igniter is shown as a spark plug I84 for high tension current and having an electrode I86 which extends near the surface of the liquid fuel in the pan I18 so that the spark will normally jump to the pan I18 which is grounded and must thus pass through the liquid fuel, serving to vaporize and ignite a portion of it. The air for combustion enters tangentially at I88, causing the-same whirling action as in previously described structures and producing a combustible mixture by contact with the liquid fuel in the pan I18 and the vapor produced therefrom; and of course this combustible mixture is ignited as soon as the spark from the electrode I88 becomes effective. If the liquid should be supplied at such a rate as to overflow the pan I18, it will accumulate on the floor I14 of the pocket which forms a trough by which the excess liquid is retained for exposure to the sweep of the air and burning gases by which it is eventually absorbed as a portion of the combustible mixture.

In the arrangement shown in Fig. 8, the frustoconical burner shell I 90 has a pocket I 92 attached to its end wall I94, and as shown in Fig. 9 the partition I98 which separates the pocket I92 from the interior of the shell I90 is formed with a pair of ports I98, I 98 which extend from top to bottom of the pocket and through which air may enter the pocket and a combustible mixture of air and fuel vapor may leave the pocket in the same manner as in previously described structures-for example, that of Figs. 3, 4, and 5. But in this arrangement the fuel entering through the pipe 200 flows directly onto the surface of the insulating sheath 202 which encases the upper portion of the electrode 204 of the igniter plug 206 and the liquid thus follows the electrode 204 downwardly and flows off the end of the electrode to the floor 208 of the pocket I 92. The spark which jumps from the end of the electrode 204 to the floor 208 is thus certain to pass through the liquid fuel itself so as to vaporize and ignite a portion of it to initiate combustion. Any accumulation of liquid fuel on the floor of the pocket I92 will flow through the ports I98 into the lowest portion of the frustoconical shell I90 with which the floor 208 of the pocket I92 is aligned so that a trough is thus provided at 2I0 in which the liquid fuel is sub- Jected to the sweep of the air and flaming products of combustion whirling around the burner chamber I90 and acting to vaporize and' ignite this fuel.

While there is shown and described herein certain structure illustrating the invention, it is to be understood that the invention is not limited thereto or thereby but may assume numerous other forms and includes all modifications, variations and equivalents coming within the scope of the following claims.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. In a heater, means forming a combustion chamber of substantially circular cross section,

air inlet means admitting air to said chamber in said pocket, igniting means in said pocket out of the path of the whirling gases in said chamber and positioned to heat and vaporize liquid fuel therein, said combustion chamber forming means including a trough to receive and hold unvaporized liquid fuel in the path of the whirling gases adjoining wall which meets said conical wall at an acute angle forming a trough, means delivering air to said chamber in transverse relation to the axis of said frusto-conical wall and producing a whirling motion of said air about said axis of said wall and over said trough, said chamber forming means including means forming a, pocket adjacent said adjoining wall,-igniting means in said pocket, fuel inlet means discharging liquid fuel into said pocket in proximity to said igniting means, said pocket communicating with the conical portion of the combustion chamber through an opening in said adjoining wall which extends to the bottom of the pocket to permit liquid fuel in said pocket to drain into the said trough for exposure to the whirling air stream in the chamber and to permit an interchange of combustion air and products of combustion between said pocket and said chamber.

3. In a heater, meansforming a combustion chamber having a frusto-conical wall and an adjoining wall which meets said conical wall at an acute angle forming a trough, means delivering air to said chamber through an opening in one of said walls, a vane adjacent said opening directing the air stream in transverse relation to the axis'of the frusto-conical wall and causing a whirling motion of said air about said axis of the frusto-conical wall and over said trough, means forming a pocket adjacent said adjoining wall in communication with the chamber to permit an interchange of combustion air and products of combustion between said chamber and said pocket, fuel inlet means supplying liquid fuel to said pocket to form with said air a combustible mixture, and igniting means in saidv pocket shielded from the air stream in the chamber.

4. In a heater, means forming a horizontal combustion chamber having a frustoconical wall and transaxial adjoining Wall which meets said conical wall at an acute angle at the larger end of its conical form to provide an annular trough, means delivering air to said chamber through an opening in one of said walls, a vane adjacent said opening directing the air stream in transverse relation to the axis of the frusto-conical wall and causing a whirling motion of said air about said axis of said wall and over said trough, said chamber includin means forming a pocket adjacent said adjoining wall in communication with the remainder of the chamber to permit an interchange of combustion air and products of combustion between said pocket and the remainder of said chamber, fuel inlet means discharging liquid fuel to said pocket to form with said air a combustible mixture, and igniting means in said pocket shielded from the air stream in the chamber, said trough serving to collect unvaporized liquid fuel and to expose it to the air stream sweepin around the chamber.

THELMA McCOLLUM. Executrix of the Last Will and Testament of Henry J. De N. McC'ollum, Deceased.

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